Hypoglycemia in patients with type 2 diabetes mellitus.

BACKGROUND: Although hypoglycemia is the most common complication of intensive diabetes therapy, there is little information about risk factors for hypoglycemia in patients with type 2 diabetes mellitus. OBJECTIVE: To determine the prevalence and predisposing factors for hypoglycemia in patients with type 2 diabetes. METHODS: Retrospective, cross-sectional analysis set in an outpatient specialty diabetes clinic. We included those patients who had baseline and follow-up visits from April 1 through October 31, 1999. Hypoglycemia was defined as typical symptoms relieved by eating, and/or blood glucose level of less than 60 mg/dL (<3.3 mmol/L). Univariate and multivariate logistic regression were used to determine the contributions to hypoglycemia of age, sex, diabetes duration, body mass index (calculated as weight in kilograms divided by the square of height in meters), fasting plasma glucose level, glycosylated hemoglobin (HbA(1c)) level, type of therapy, and previous episodes at the follow-up visit. RESULTS: We studied 1055 patients. Prevalence of hypoglycemic symptoms was 12% (9/76) for patients treated with diet alone, 16% (56/346) for those using oral agents alone, and 30% (193/633) for those using any insulin (P<.001). Severe hypoglycemia occurred in only 5 patients (0.5%), all using insulin. Multiple logistic regression analysis demonstrated that insulin therapy, lower HbA(1c) level at follow-up, younger age, and report of hypoglycemia at the baseline visit were independently associated with increased prevalence of hypoglycemia. There were no significant predictors of severe hypoglycemia. CONCLUSIONS: Mild hypoglycemia is common in patients with type 2 diabetes undergoing aggressive diabetes management, but severe hypoglycemia is rare. Concerns about hypoglycemia should not deter efforts to achieve tight glycemic control in most patients with type 2 diabetes.

Comorbidity and glycemic control in patients with type 2 diabetes.

BACKGROUND: It is commonly believed that good glycemic control is hard to achieve in patients with diabetes mellitus and concurrent chronic illnesses. OBJECTIVE: To determine the impact of comorbidity on glycemic control at presentation and subsequent follow-up in patients with type 2 diabetes. METHODS: We studied 654 consecutive patients who presented to a diabetes clinic in 1997. Comorbidity was rated using the Chronic Disease Score (CDS) index, which is a validated, weighted score that takes into account the patient's age, sex, and classes of medications. Univariate and multivariate linear regressions were used to determine the contribution of age, body mass index (calculated as weight in kilograms divided by the square of height in meters), diabetes duration, type of therapy, and CDS to initial hemoglobin A(1c) (HbA(1c)) level. A similar analysis was performed for the 169 patients with follow-up HbA(1c) levels 6 months after presentation. RESULTS: Patients were 90% African American, and 66% female, with average age of 53 years. Average diabetes duration was 5 years; body mass index, 33; HbA(1c) level, 8.8%; and CDS, 1121 (range, 232-7953). At presentation, patients with higher CDSs tended to be older and to have a lower HbA(1c) level, but multivariate linear regression showed that receiving pharmacological therapy, younger age, and having a lower C-peptide level were the only significant contributors to HbA(1c) level. In the 169 follow-up patients, presenting characteristics were not significantly different from those of the full cohort: average initial HbA(1c) level was 8.8%; CDS, 1073. Their HbA(1c) level at 6 months averaged 7.5% and the CDS had no significant impact on their follow-up HbA(1c) level. CONCLUSION: Comorbidity does not appear to limit achievement of good glycemic control in patients with type 2 diabetes.

Use of the Physician Insurers Association of America database as a surveillance tool for diabetes-related malpractice claims in the U.S.

OBJECTIVE: To examine the available national surveillance data on malpractice claims associated with diabetes and to determine the medical specialties having the highest number of claims and the classes and costs of filed claims relating to diabetes. RESEARCH DESIGN AND METHODS: Data was abstracted from the Data Sharing Reports (DSRs) of the Physicians Insurers Association of America (PIAA), as well as a search of the PIAA's computerized database for the period spanning 1 January 1985 to 31 December 1996. Data on numbers of claims, medical causes of loss, indemnity paid, demographics of claimants and physicians, severity, and medical specialties with diabetes-related claims were available. RESULTS: A total of 906 diabetes claims were reported to PIAA, and the total indemnity paid was $26,892,848. A significant downward trend (P = 0.004) was noted for the period between 1993 and 1996. Diabetes claimants were older and predominantly male, relative to all claimants. Ophthalmology, internal medicine, and general and family practice had the highest rates of reported claims at 16.5, 13.6, and 13.4 diabetes claims per 1,000 claims, respectively. Of the diabetes-related injuries, 44% occurred in the practitioners office, as compared with 27% for all claims. A greater proportion of diabetes claims were associated with the highest level of severity of injury with respect to all claims compiled by the PIAA. CONCLUSIONS: The database of the PIAA can be a useful resource to monitor trends in diabetes-related malpractice. Further study into whether claims result from lack of adherence to practice guidelines is needed. Prevention programs designed to reduce the liability among high-risk specialties may also lead to improved care for the patient with diabetes.

Effects of sickle cell trait and hemoglobin C trait on determinations of HbA1c by an immunoassay method.

OBJECTIVE: A number of studies, including the Diabetes Control and Complications Trial (DCCT), have shown that good glycemic control, as assessed by GHb measurements, can reduce the chronic complications of diabetes. The National Glycohemoglobin Standardization Program (NGSP) was established to insure that GHb measurements by different methods were comparable and could be related to the candidate reference method used in the DCCT. The measurement of HbA1c in patients with Hb variants is one area not directly addressed by the NGSP. Therefore, we assessed the comparability of two DCCT-traceable methods in samples with Hb variants. RESEARCH DESIGN AND METHODS: Samples containing HbAA, HbAC, and HbAS were collected from diabetic and nondiabetic patients. HbA1c concentrations were measured by a high-performance liquid chromatography method (Bio-Rad Diamat) and an immunoassay that is suitable for use in a physician's office (Bayer DCA 2000). RESULTS: The two methods compared well for samples with HbAA and HbAS. However, for samples containing HbAC the immunoassay method showed relative positive biases of 8.4 and 10.4% at HbA1c levels of 7 and 9%, respectively, such that the two methods would not be judged comparable according to NGSP guidelines. CONCLUSIONS: The DCA 2000 HbA1c immunoassay method showed significant positive bias in patients with HbC trait. One possible clinical implication of this overestimation is overly rigorous glycemic control with a concomitant increase in hypoglycemia. This may be especially important in certain ethnic populations, such as African-Americans, who have a relatively high prevalence of HbC trait.

Lipoprotein (a) levels in African-Americans with NIDDM.

OBJECTIVE: The purpose of this study was to investigate possible relationships between lipoprotein (a) [Lp(a)] levels and NIDDM in African-Americans. The objectives were to identify associations between Lp(a) levels of subjects with and without NIDDM and to determine the influence of glycemic control, determined by GHb, and of mode of therapy on Lp(a) levels. RESEARCH DESIGN AND METHODS: We studied [4] African-American subjects, 103 with NIDDM and 38 without NIDDM. Their Lp(a) levels, GHb levels, and apolipoprotein (a) [apo(a)] isoforms were determined. Clinical information, including mode of therapy (sulfonylurea, insulin, or no pharmacological therapy), date of diagnosis, and medical history, was obtained by chart review and patient interview. RESULTS: There was no significant difference in median Lp(a) levels between the non-NIDDM (25.5 mg/dl) and NIDDM (24.0 mg/dl) study subjects. No statistically significant difference was found in Lp(a) levels when NIDDM patients with GHb < 12.3% were compared to those with GHb > or = 12.3% (P = 0.096). An inverse relationship was found between apo(a) root-mean-square isoform size and Lp(a) level (r2 = 0.091, P = 0.0035). Analysis of the cases by mode of therapy indicates that there is evidence of an increased median level of Lp(a) in African-Americans with NIDDM on insulin therapy relative to those on sulfonylurea (34.0 vs. 16.0 mg/dl; P = 0.013) and to nondiabetic subjects (34.0 vs. 25.5 mg/dl; P = 0.043). CONCLUSIONS: We conclude that the level of plasma Lp(a) is higher in African-Americans with NIDDM who are being treated with insulin when compared to those on sulfonylurea therapy and to those who are non-NIDDM subjects, and this does not seem to be due to genetic variance or method bias.

What do internal medicine residents need to enhance their diabetes care?

OBJECTIVE: To identify areas that should be targeted for improvement in care, we examined internal medicine resident practice patterns and beliefs regarding diabetes in a large urban hospital outpatient clinic. RESEARCH DESIGN AND METHODS: Internal medicine residents were surveyed to assess the frequency at which they performed key diabetes quality of care indicators. Responses were compared with recorded performance derived from chart and laboratory database reviews. Resident attitudes about diabetes were determined using the Diabetes Attitude Survey for Practitioners. Finally, an eight-item scale was used to assess barriers to diabetes care. RESULTS: Both self-described and recorded performance of recommended diabetes services short of national recommendations. For yearly eye examinations and lipid screening, recorded performance levels were similar to trainees' reports. However, documented inquiries about patient self-monitoring of blood glucose, performance of foot examinations, and urine protein screening were lower than trainees' reports. Some 49% of the residents selected a target HbA1c of 6.6-7.5% as an attainable goal, yet half of the patients using oral agents or insulin had HbA1c values > 8.0%. No differences in self-described or recorded performance were found by year of training. Most residents did not perceive themselves to need additional training related to diabetes care, and residents were generally neutral about patient autonomy. Patient nonadherence and time constraints within the clinic were most often cited as barriers to care. CONCLUSIONS: The study identifies several areas that require improvement in resident care of diabetes in the ambulatory setting. Because experience during training contributes to future practice patterns, developing a program that teaches trainees how to implement diabetes practice guidelines and methods to achieve optimal glycemic control may be key to future improvements in the quality of diabetes care.

The potentially poor response to outpatient diabetes care in urban African-Americans.

OBJECTIVE: HbA1c levels can be reduced in populations of diabetic patients, but some individuals may exhibit little improvement. To search for reasons underlying differences in HbA1c outcome, we analyzed patients managed in an outpatient diabetes clinic. RESEARCH DESIGN AND METHODS: African-Americans with type 2 diabetes were categorized as responders, intermediate responders or poor responders according to their HbA1c level after 1 year of care. Logistical regression was used to determine baseline characteristics that distinguished poor responders from responders. Therapeutic strategies were examined for each of the response categories. RESULTS: The 447 patients had a mean age and disease duration of 58 and 5 years, respectively, and BMI of 32 kg/m2. Overall, the mean HbA1c level fell from 9.6 to 8.1% after 12 months. Mean HbA1c levels improved from 8.8 to 6.2% in responders, and from 9.5 to 7.9% in intermediate responders. In poor responders, the average HbA1c level was 10.8% on presentation and 10.9% at 1 year. The odds of being a poor responder were significantly increased with longer disease duration, higher initial HbA1c level, and greater BMI. Although doses of oral agents and insulin were significantly higher among poor responders at most visits, the acceleration of insulin therapy did not occur until late in the follow-up period. CONCLUSIONS: Clinical diabetes programs need to devise methods to identify patients who are at risk for persistent hyperglycemia. Whereas patient characteristics explain some heterogeneity of HbA1c outcome (and may aid in earlier identification of patients who potentially may not respond to conventional treatment), insufficient intensification of therapy may also be a component underlying the failure to achieve glycemic goals.

Diabetes in urban African-Americans. XIX. Prediction of the need for pharmacological therapy.

OBJECTIVE: To develop a prediction rule that will identify patients who will require pharmacological therapy within 6 months of first presentation to a diabetes clinic. RESEARCH DESIGN AND METHODS: Among the patients who came to the Grady Diabetes Clinic between 1991 and 1997, we randomized 557 frequent attenders to a development group and 520 frequent attenders to a validation group. Using multiple logistical regression, we derived a prediction rule in the development group to project whether patients would require pharmacological intervention to achieve HbA1c levels <7% after 6 months. The utility of the prediction rule was then confirmed in the validation group and tested prospectively on an additional group of 93 patients who presented from 1997 to 1998. Performance of the prediction rule was assessed using receiver operating characteristic (ROC) curves. RESULTS: The rule (-4.469 + 1.932 x sulfonylurea Rx + 1.334 x insulin Rx + 0.196 x duration + 0.468 x fasting glucose, where "Rx" indicates a prescription) predicted the need for pharmacological intervention in the development group (P < 0.0001). Use of insulin or sulfonylurea therapy at presentation, duration of diabetes, and fasting glucose levels were significant predictors of the future need for pharmacological management. The prediction rule also performed well in the validation group (positive predictive value 90%, correlation between predicted and observed need for medical management 0.99). ROC curves confirmed the value of the prediction rule (area under the curves was 0.91 for the development group, 0.85 for the validation group, and 0.81 for the prospective group). CONCLUSIONS: Early identification of individuals who will require pharmacological intervention to achieve national standards for glycemic control can be achieved with high probability, thus allowing for more efficient management of diabetes.

Diabetes in urban African-Americans. XVII. Availability of rapid HbA1c measurements enhances clinical decision-making.

OBJECTIVE: To assess the impact of rapid-turnaround HbA1c results on providers' clinical decision-making and on follow-up HbA1c levels. RESEARCH DESIGN AND METHODS: The research design was a randomized clinical trial in which rapid HbA1c results were made available to providers on even days of the month (rapid, n = 575), but delayed by 24 h on odd days (conventional, n = 563). Adjustment of therapy for patients with type 2 diabetes was considered appropriate if therapy was intensified for HbA1c values >7% or not intensified for HbA1c values < or =7%. A post-hoc analysis was also performed using patients (n = 574) who returned for follow-up 2-7 months later to ascertain the effect of rapid HbA1c availability on subsequent glycemic control. RESULTS: Rapid HbA1c availability resulted in more appropriate management compared with conventional HbA1c availability (79 vs. 71%, P = 0.003). This difference was due mainly to less frequent intensification when HbA1c levels were < or =7% (10 vs. 22%, P < 0.0001) and slightly to more frequent intensification for patients with HbA1c values >7% (67 vs. 63%, P = 0.33). For both groups, intensification was greatest for patients on insulin (51%) compared with patients on oral agents (35%) and diet alone (14%) (P < 0.0001). Regression analysis confirmed that providers receiving conventional HbA1c results were more likely to intensify therapy in patients who already had HbA1c levels < or =7%. Over 2-7 months of follow-up, HbA1c rose more in patients with conventional HbA1c results compared with rapid results (0.8 vs. 0.4%, P = 0.02). In patients with initial HbA1c >7%, rapid HbA1c results had a favorable impact on follow-up HbA1c independent of the decision to intensify therapy (P = 0.03). CONCLUSIONS: Availability of rapid HbA1c determinations appears to facilitate diabetes management. The more favorable follow-up HbA1c profile in the rapid HbA1c group occurs independently of the decision to intensify therapy, suggesting the involvement of other factors such as enhanced provider and/or patient motivation.

Diabetes in urban African-Americans. XVI. Overcoming clinical inertia improves glycemic control in patients with type 2 diabetes.

OBJECTIVE: Diabetes care can be limited by clinical inertia-failure of the provider to intensify therapy when glucose levels are high. Although disease management programs have been proposed as a means to improve diabetes care, there are few studies examining their effectiveness in patient populations that have traditionally been underserved. We examined the impact of our management program in the Grady Diabetes Unit, which provides care primarily to urban African-American patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: We assessed glycemic outcomes in patients with type 2 diabetes who had an intake evaluation between 1992 and 1996 and who were identified on the basis of compliance with keeping the recommended number of return visits. For 698 patients, we analyzed changes in HbA1c values between baseline and follow-up visits at 6 and 12 months, and the proportion of patients achieving a target value of < or =7.0% at 12 months. Since a greater emphasis on therapeutic intensification began in 1995, we also compared HbA1c values and clinical management in 1995-1996 with that of 1992-1994. RESULTS: HbA1c averaged 9.3% on presentation. After 12 months of care, HbA1c values averaged 8.2, 8.4, 8.5, 7.7, and 7.3% for the 1992-1996 cohorts, respectively, and were significantly lower compared with values on presentation (P < 0.0025); the average fall in HbA1c was 1.4%. The percentage of patients achieving a target HbA1c < or =7.0% improved progressively from 1993 to 1996, with 57% of the patients attaining this goal in 1996. Mean HbA1c after 12 months was 7.6% in 1995-1996, significantly improved over the level of 8.4% in 1992-1994 (P < 0.0001). HbA1c levels after 12 months of care were lower in 1995-1996 versus 1992-1994, whether patients were managed with diet alone, oral agents, or insulin (P < 0.02). Improved HbA1c in 1995-1996 versus 1992-1994 was associated with increased use of pharmacologic therapy CONCLUSIONS: Structured programs can improve glycemic control in urban African-Americans with diabetes. Self-examination of performance focused on overcoming clinical inertia is essential to progressive upgrading of care.

The pattern of dyslipidemia among urban African-Americans with type 2 diabetes.

OBJECTIVE: To analyze lipid profiles from a large sample of African-American patients with type 2 diabetes who receive care at an urban outpatient diabetes clinic. RESEARCH DESIGN AND METHODS: Fasting serum lipid profiles of 4,014 African-Americans and 328 Caucasians with type 2 diabetes were retrieved from a computerized registry. American Diabetes Association criteria were applied to classify LDL cholesterol, HDL cholesterol, and triglyceride (TG) levels into risk categories. The proportion of patients who had none, one, two, and three lipoprotein concentrations outside of recommended clinical targets was examined. Multiple logistical regression analyses were performed to determine the influence of sex and race on the probability of having a lipid level outside of the recommended target. RESULTS: The percentages of African-Americans with high-, borderline-, and low-risk LDL cholesterol concentrations were 58, 26, and 16%, respectively, and the percentages for Caucasians were 54, 29, and 16%, respectively (P = 0.51). For HDL cholesterol, 41, 33, and 26% of African-Americans were in the high-, borderline-, and low-risk categories, respectively, compared with 73, 18, and 9% of Caucasians, respectively (P < 0.0001). Nearly 81% of African-Americans had TG concentrations that were in the low-risk category compared with only 50% of Caucasians. More women than men had high-risk LDL and HDL cholesterol profiles. The most common pattern of dyslipidemia was an LDL cholesterol level above target combined with an HDL cholesterol level below target, which was detected in nearly 50% of African-Americans and 42% of Caucasians. African-Americans had lower odds of having an HDL cholesterol or TG level outside of target. African-American women, compared to men, had greater probabilities of having abnormal levels of LDL and HDL, but a lower likelihood of having a TG level above goal. CONCLUSIONS: In a large sample of urban type 2 diabetic patients receiving care at a diabetes treatment program, race and sex differences in serum lipid profiles were present. Because hypertriglyceridemia was rare among African-American subjects, interventions will need to focus primarily on improving their LDL and HDL cholesterol levels. Further studies are required regarding how to best adapt these observed differences into more effective strategies to optimize lipid levels for this population of diabetic patients and to determine whether similar patterns of dyslipidemia occur in other clinical settings.

Expression of thyroid hormone receptor beta 2 in rat hypothalamus.

A polymerase chain reaction based assay was used to evaluate expression of thyroid hormone receptor beta 2 mRNA in rat hypothalamus. Expression was detected in the arcuate, ventromedial and paraventricular nuclei, as well as the median eminence. Trace expression was found in the dorsomedial nucleus, but no expression of thyroid hormone receptor beta 2 was detected in the lateral hypothalamus or the preoptic region. The results indicate that, contrary to previous belief, expression of thyroid hormone receptor beta 2 is not confined to the anterior pituitary.

Naloxone increases the frequency of pulsatile luteinizing hormone secretion in women with hyperprolactinemia.

The ability to change the frequency and amplitude of pulsatile GnRH secretion may be an important mechanism in maintaining regular ovulatory cycles. Hyperprolactinemia is associated with anovulation and slow frequency LH (GnRH) secretion in women. To assess whether the slow frequency of LH (GnRH) secretion is due to increased opioid activity, we examined the effect of naloxone infusions in eight amenorrheic hyperprolactinemic women (mean +/- SE, serum PRL, 160 +/- 59 micrograms/L). After a baseline period, either saline or naloxone was infused for 8 h on separate days, and LH was measured in blood obtained at 15-min intervals. Additional samples were obtained for plasma FSH, PRL, estradiol, and progesterone. Responses to exogenous GnRH were assessed at the end of the infusions. LH pulse frequency increased in all subjects from a mean of 4.0 +/- 0.5 pulses/10 h (mean +/- SE) during saline infusion to 8.0 +/- 1.0 pulses/10 h during naloxone infusion (P less than 0.01). LH pulse amplitude did not change, and mean plasma LH increased from 7.4 +/- 0.8 IU/L (+/- SE) to 11.2 +/- 1.5 IU/L during naloxone (P less than 0.01). A small but significant increase was seen in mean plasma FSH. Plasma PRL, estradiol, and progesterone were unchanged by naloxone infusion. These data suggest that elevated serum PRL reduces the frequency of LH (GnRH) secretion by increasing hypothalamic opioid activity and suggest that the anovulation in hyperprolactinemia is consequent upon persistent slow frequency LH (GnRH) secretion.

Expression of erbA alpha and beta mRNAs in regions of adult rat brain.

The proto-oncogenes erbA alpha and erbA beta together encode three functional thyroid hormone receptors (erbA alpha 1, beta 1, and beta 2), as well as two proteins (erbA alpha 2 and alpha 3) that do not bind T3. The erbA alpha 2 protein has been shown to inhibit the T3 inductive effects of functional receptors, and alpha 2 mRNA is expressed at high levels in adult rat brain. Thus, expression of erbA alpha 2 may explain the observation that adult rat brain is not a T3 responsive organ, despite the presence of T3 receptors. However, expression of the different erbA mRNAs has not been studied within distinct regions of rat brain. To gain further insight into the roles of these molecules, we have used polymerase chain reaction to investigate the expression of all five erbA mRNAs within discrete regions of adult rat brain. The results indicate that all three erbA alpha mRNAs are expressed in all regions studied (brainstem, cerebellum, cortex, hippocampus, pituitary, quadrigeminal plate, striatum, and thalamus). All regions contained less erbA alpha 3 RNA than either alpha 1 or alpha 2. Expression of alpha 2 exceeded that of alpha 1 in all regions except striatum. ErbA beta 1 was expressed in all brain regions, whereas erbA beta 2 was confined to the pituitary.

Rapid diagnosis of enterohemorrhagic Escherichia coli O157:H7 directly from fecal specimens using immunofluorescence stain.

Serotype O157:H7 is most frequently encountered among verotoxin-producing Escherichia coli. Most laboratories use MacConkey-sorbitol agar as a screening medium. Presumptive identification of sorbitol-negative colonies is then accomplished by latex agglutination or biochemical tests with serologic confirmation, which requires 18-36 hours for completion. This study attempted to detect E coli O157:H7 directly from stool specimens by direct immunofluorescence (DIF) antibody staining to provide quicker turnaround (< 2 hours). A total of 336 abnormal fecal samples (bloody, watery, semi-liquid, or mucoid) were examined by this method. Results were compared with those of culture. Direct immunofluorescence antibody staining of the direct fecal smear detected all isolates of E coli O157 that were recovered by culture, including nonmotile strains, strains possessing the H7 flagellar antigen, and one strain with a flagellar antigen other than H7. Optimum results were achieved when specimens were pretreated with 5% bleach and centrifugation. No false-negative results were obtained with bleach-pretreated stool samples.

Rapid recovery of mycobacteria from clinical specimens using automated radiometric technic.

Automated radiometric technic (BACTEC Johnston Laboratories, Towson, MD) was compared with conventional mycobacterial culture procedure (Lowenstein-Jensen plus Gruft modification of Lowenstein-Jensen) in this study of 1,000 clinical specimens. In addition, 8-azaguanine inhibition was tested by radiometric technic as a rapid procedure for the differentiation of Mycobacterium tuberculosis from other mycobacterial species. A total of 59 mycobacteria was recovered. Of 28 clinically significant isolates (M. tuberculosis, M. kansasii, M. avium, M. fortuitum), the BACTEC system detected 26 (93%). Conventional methods recovered 23 (82%). The BACTEC system required an average of seven days to recover M. tuberculosis from smear-positive specimens compared with 18 days required by Lowenstein-Jensen or Gruft slants. From smear-negative specimens, the BACTEC detected M. tuberculosis in an average of 20 days versus 28 days by conventional procedure. All 20 isolates of M. tuberculosis were inhibited by 8-azaguanine, whereas 39 isolates of mycobacteria other than M. tuberculosis were not inhibited. The BACTEC system accomplishes more rapid recovery of mycobacteria and provides a higher yield than conventional methods.

Rapid detection of insignificant bacteriuria by concomitant use of Lumac system and Gram's stain.

The Lumac system, which assays bacterial ATP by bioluminescence, is a rapid method (less than 1 hour) for detection of bacteriuria. Conventional culture by calibrated loop technic and the Lumac system were compared using 2,000 urine specimens. Interpretation of Gram's stains of uncentrifuged specimens in addition to results of the Lumac system provided a second comparison with culture. Using a criterion of greater than or equal to 10(4) CFU/mL, conventional culture yielded 17% of the 2,000 specimens positive for bacteriuria. By Lumac + smear 27% were positive opposed to 41% positive by the Lumac system alone. The Lumac + smear method produced sensitivity (97%), specificity (88%), positive predictive value (62%), and negative predictive value (99.3%). False negative rates by the Lumac alone and Lumac + smear were 0.65% and 0.5%, respectively.

A rapid diagnosis of Campylobacter enteritis by direct smear examination.

Diagnosis of Campylobacter enteritis by direct smear examination of stool specimens, using 1% aqueous basic fuchsin, was compared with a conventional cultural method (Campy-BAP). After examination of 485 stool specimens the direct smear method produced a sensitivity and specificity of 94% and 99.5%, respectively.

False negative hepatitis B surface antigen detection in dialysis patients due to excess surface antigen: postzone phenomenon.

Renal dialysis patients are well known to have a high incidence of hepatitis B carrier state. In studying a group of 63 long-term dialysis patients, 10 were found to be positive for hepatitis B surface antigen by radioimmunoassay (RIA). Surprisingly, however, only three of these RIA positive patients were positive by counter immunoelectrophoresis (CIEP). The discrepancy could not be accounted for by the difference in sensitivity of the two methods. The cause for the negative reactions by CIEP in seven patients was found to be the marked excess surface antigen in these sera which produced false negative results by the postzone phenomenon. After dilution all seven sera were positive by CIEP, requiring a dilution up to 1/20 to produce a positive result. Also, all seven sera were positive by the less sensitive Ouchterlony double diffusion.

Comparison of four commercial urinary albumin (microalbumin) methods: implications for detecting diabetic nephropathy using random urine specimens.

The results of four urinary albumin methods used to identify patients with early diabetic renal disease were compared using random urine samples from healthy and diabetic patients. These methods were the Beckman Array and Behring BNAI immunonephelometric methods, the Dade aca particle-enhanced turbidimetric inhibition immunoassay method, and the INCSTAR SPQ immunoturbidimetric method. The albumin/creatinine ratio reference interval was found to be 2-20 mg albumin/g creatinine (mg/g) for the Array and 3.5-27.5 mg/g for the aca method. All four methods were compared using urines from a group of diabetic and nondiabetic patients. The BNAI, SPQ and Array methods compared well with one another while the aca demonstrated a positive bias of almost 60% at the 30 mg/g and 300 mg/g levels with certain lots of reagent and calibrator. Calibrator cross-over experiments demonstrated that some of the positive bias of the aca method could be accounted for by calibrator differences.